So, my private blockchain became out of sync and one of the nodes reset to block 0 – it then synced up with the other nodes. The node that went to block 0 is the node that is providing the rpc port for Metamask.

I believe this has something to do with the fact that in order to catch up with the other nodes, this node had to 'fast-forward', so it is unable to access older blocks. Is there a way to do a full-sync at this point or is there a way that I should be starting the chains in order to ensure that they are fully synced? What else could possibly be going wrong?